The technical field of this invention is electronic communication systems and, in particular, systems for locating and/or retrieving objects by electromagnetic interrogation of a spatial region to detect the presence (or absence) of an object.
Searching for possessions, tools and other objects is often a time-consuming task. Since the beginning of history, people have sought to solve this problem in many ways by devising implements to help keep track of useful objects. For example, one of the earliest metal implements devised by man was the bell, used by shepherds and other handlers of animals to locate their flocks or herds. As civilization has developed, so has the need for locating and identifying useful objects or possessions. Modern society faces an unparalleled proliferation of personal and business objects, many of which are either visually indistinguishable from each other or are difficult to examine readily. Examples of such objects include office files, business inventory, retail merchandise, luggage, freight and other commercial or personal items.
Office files are a particularly perplexing problem since it is common for more than one individual to work on a file, e.g., to add papers, make notations or otherwise review and/or revise the file's contents. Office productivity is lost whenever a file is misplaced or can not be located. Accuracy and efficiency are also lost whenever papers can not be placed into an appropriate file in a timely fashion.
Another area where tracking of objects is of critical importance is in shipping, where packages destined for diverse locations must be stored and then routed to particular carriers or vehicles. This problem is particularly acute in luggage handling where lost articles of luggage can be especially vexing to passengers. At present, visual tags are used to identify the destination of luggage. However, there is no simple way to verify if all the luggage intended for a particular destination has been loaded on the proper carrier, and it is difficult, even with visual tags, to find misplaced or misrouted items of luggage.
Similarly, the management of retail items, such as clothing, or stock parts for manufacturing purposes often requires inventory-taking. If an item can not be located, e.g., an article of clothing in a particular size or a manufacturing part of particular characteristics, then a sale is lost or a manufacturing order goes unfilled. Moreover, the business manager may order supplemental items, not knowing that a supply exists on the premises in some unidentified location.
Recently, a number of electronic finding aids have been developed. For example, many cordless telephones now come equipped with a radio receiver to assist in their location in event that the telephone headset is misplaced. A transmitter incorporated into the charger/line interface module emits a signal that causes the headset to ring when a button is activated on the interface module. Similarly, the problem of lost keys can sometimes be remedied by a key chain tag which generates an alarm in response to certain sonic signals, such as a sharp whistle or a loud slap.
Unfortunately, conventional electronic finding aids are not capable of tracking large inventories or large numbers of files. In many cases, the simplicity of the finding aid system (e.g., the nature of the transmission signal or the receiver) makes it impossible to distinguish one object from another. In other cases, the overlap of signals from various sources causes too much interference when a plurality of objects need to be located. There exists a need for better electronic location systems, particularly systems that can accommodate the tracking of large numbers of files, items of inventory or the like.
There also exists a need for systems and methods that would permit automatic inventory-taking of files or merchandise on a regular basis (e.g. daily or on another periodic basis), as well as permit immediate or real time location and retrieval of objects in diverse environments.
Moreover, simple systems for locating and/or retrieving objects which can be incorporated into a conventional office or commercial data processing or communications infrastructure would likewise enhance efficiency while also achieving a cost economy as a result of integration with existing hardware and/or software.